7. Retardation Factor

Try these first

1. 1.

   What does the retardation factor measure?

   Hint

   Think about diffusion in general.

2. 2.

   Define porosity in your own words.

   Hint

   Consider sediment composition.

3. 3.

   What is the primary effect of the retardation factor?

   • Increases diffusion rate
   • Decreases diffusion rate
   • No effect on diffusion

   Hint

   Remember the definition of retardation.

4. 4.

   True or False: The local equilibrium assumption assumes that adsorption and desorption rates are always equal.

   • True
   • False

   Hint

   Think about interactions in equilibrium.

5. 5.

   Calculate the retardation factor for a sediment with a bulk density of 1.5 g/cm³ and a distribution coefficient (Kd) of 0.8.

   Hint

   Use the retardation factor equation.

6. 6.

   Describe how you would set up a laboratory experiment to test how porosity impacts the effective diffusion coefficient.

   Hint

   Consider how you will measure the tracer's progress!